MindyM

The fact is says 'AGND' I assume this is analogue ground not Earth Ground.
This sort of high lights the problem where the term GND is used across the board, whether earth ground or not.
It is not allowed in most jurisdictions to connect neutral and earth ground anywhere but at the service or re-established local supply source.

Alex_T

You can't guarantee that there will be 0V between Neutral and Gnd. Although they may be connected together at some point in a mains distribution system, wiring from that point on can pick up all sorts of voltages from spurious ground currents and interference.
AGND is a reference point for your circuit.